Investigation on Risk Factors of Ventilator-Associated Pneumonia in Acute Cerebral Hemorrhage Patients in Intensive Care Unit

Ventilator-associated pneumonia (VAP) is a predominant factor of pulmonary infection. We analyzed the risk factors of VAP with acute cerebral hemorrhage in intensive care unit (ICU) by univariate and multivariate logistic regression analyses. After comparison of 197 cases of the VAP and non-VAP patients, we found that age > 65 years (P = 0.003), smoke (P = 0.003), coronary heart disease (P = 0.005), diabetes (P = 0.001), chronic obstructive pulmonary disease (COPD) (P = 0.002), ICU and hospital stay (P = 0.01), and days on mechanical ventilation (P = 0.01) were significantly different, indicating that they are risk factors of VAP. All the age > 65 years (OR = 3.350, 95% CI = 1.936–5.796, P ≤ 0.001), smoke (OR = 3.206, 95% CI = 1.909–5.385, P ≤ 0.001), coronary heart disease (OR = 3.179, 95% CI = 1.015–4.130, P = 0.017), diabetes (OR = 5.042, 95% CI = 3.518–7.342, P ≤ 0.001), COPD (OR = 1.942, 95% CI = 1.258–2.843, P = 0.012), ICU and hospital stay (OR = 2.34, 95% CI = 1.145–3.892, P = 0.038), and days on mechanical ventilation (OR = 1.992, 95% CI = 1.107–3.287, P = 0.007) are independent risk factors of VAP. After observation of patients with 6 months of follow-up, the BI score was significantly lower in VAP than that in non-VAP, and the rebleeding rate and mortality rate were significantly higher in VAP than those in non-VAP. Thus, the prognosis of the patients with acute cerebral hemorrhage and VAP in ICU is poor.


Introduction
Mechanical ventilation is a supportive treatment for the maintenance of respiratory function [1,2], which was used in the perioperative period and all types of critically ill patients in the rescue phase, especially in the occurrence of acute lung injury, acute respiratory distress syndrome, and acute cerebral hemorrhage [3][4][5]. Mechanical ventilation simulates physiological respiration, which ensures oxygen supply and meets the needs of oxygen [4]. However, mechanical ventilation is di erent from the physiological ventilation model, which can act as a factor causing mechanical ventilation-related lung injury [6,7]. Clinically, during the use of mechanical ventilation, even if the patient's previous lung function is normal, there may be local in ammatory response, a certain degree of lung injury, and even acute lung injury [8][9][10].
Pulmonary infection is one of the most common complications in patients with acute cerebral hemorrhage, which directly a ects the prognosis of those patients [11][12][13]. Ventilator-associated pneumonia (VAP) is de ned as the onset of pneumonia in patients with tracheal intubation or tracheotomy after 48 h of mechanical ventilation [14,15]. After withdrawal or extubation, pneumonia within 48 h is still VAP. VAP is the most serious type of hospital-acquired pneumonia, with the incidence rate of 15% to 60% and the mortality rate of 25% to 76%, and is also the major risk factor of patients in intensive care unit (ICU) [16][17][18]. VAP is a predominant factor of pulmonary infection in patients with acute cerebral hemorrhage. VAP not only prolongs the hospital stay but also increases the cost of treatment. Acute cerebral hemorrhage can directly a ect the prognosis of patients, prolong the hospital stay, increase the medical costs, and accelerate the deterioration of the disease, so it is of great signi cance to prevent VAP occurrence by early identi cation of the risk factors of acute cerebral hemorrhagic-related pneumonia and control the predictable factors in the safe range [17,19,20].
In this study, the clinical data of patients with acute cerebral hemorrhage in our hospital emergency intensive care unit in recent years were retrospectively analyzed to nd out the risk factors of VAP in acute cerebral hemorrhage patients. Our study provides the theoretical basis for early clinical decision and might improve the life expectancy and quality of life of patients with acute cerebral hemorrhage.

Clinical Data.
One hundred ninety-seven cases of patients with acute cerebral hemorrhage with or without mechanical ventilation from December 2014 to December 2016 in the Emergency Intensive Care Unit, Sichuan Provincial People's Hospital, China, were enrolled after approval by the Medical Ethic Committee of Sichuan Provincial People's Hospital. Written informed consents conforming to the tenets of the Declaration of Helsinki were obtained from each participant prior to the study. e acute cerebral hemorrhage of patients was con rmed by skull CT and head MRI examination. All the patients are in line with the guideline of diagnosis and treatment of hospital-acquired pneumonia in China made by the Chinese Society of Respiratory Diseases.

Data Analysis.
A retrospective analysis of the clinical data of 197 patients with acute cerebral hemorrhage was performed, including age, gender, past history (smoke, coronary heart disease, hypertension, and diabetes), COPD, ICU and hospital stay, and days on mechanical ventilation. Moreover, the correlation analysis of the indicators with VAP was performed.

Statistical
Analysis. Using SPSS19.0 software for statistical analysis, count data were compared by χ 2 test and Fisher's exact probability test for a table of % frequency data, and the in uential factors of VAP were analyzed by univariate and multivariate logistic regression analyses. P < 0.05 was statistically signi cant.

Univariate Logistic Regression Analysis of the Risk Factors of VAP.
In the patients with ventilator-associated pneumonia (VAP), there were 46 males and 36 females, aged from 26 to 79, with an average age of 55.47 ± 13.53 years ( Table 1). In the non-VAP group, there were 66 males and 49 females, aged from 27 to 77, with an average age of 56.52 ± 16.23 years. After comparison of the VAP and non-VAP patients with acute cerebral hemorrhage, we found that age > 65 years (P � 0.003), smoke (P � 0.003), coronary heart disease (P � 0.005), diabetes (P � 0.001), chronic obstructive pulmonary disease (COPD) (P � 0.002), ICU and hospital stay (P � 0.01), and days on mechanical ventilation (P � 0.01) were signi cantly di erent, indicating that they are risk factors of VAP.

e Mortality Rate and Rebleeding Rate in Patients with
VAP Were Higher than ose Without VAP. After observation of patients with 6 months of follow-up, the BI score, rebleeding rate, and mortality rate were calculated. e BI score was signi cantly lower in VAP than that in non-VAP (P � 0.003). e rebleeding rate and mortality rate

Discussion
With the accelerated process of aging, the incidence of cerebrovascular disease in China increased with year and has the trend of rejuvenation, which is a serious threat to people's health [21]. Ventilator-associated pneumonia (VAP) is one of the most common complications after treatment of acute cerebral hemorrhage [3][4][5]. e serious pulmonary infection directly a ects the prognosis of patients and even leads to death. Cerebral hemorrhage is a common disease that seriously damages people's health and life. e cerebral hemorrhage patients with more serious illness often entered the ICU. e study showed that patients are prone to VAP. is study showed 197 cases of acute cerebral hemorrhage patients. Among them, 82 cases are VAP, with the incidence of 41.6%, showing a very high incidence of VAP in ICU patients with acute cerebral hemorrhage. is might be due to the occurrence of a stress state in patients with acute cerebral hemorrhage, which increased the susceptibility to infection of VAP by decreasing the body resistance, inducing intracranial hypertension, a ecting the thalamic function and the autonomic nerve function disorder, and inducing pulmonary hypertension and pulmonary capillary congestion. In addition, ICU is the gathering place of critically ill patients and the most serious hospital infection [22,23]. We observed that the BI score was signi cantly lower in VAP than that in non-VAP. e rebleeding rate and mortality rate were signi cantly higher in VAP than those in non-VAP. It was suggested that VAP can seriously a ect the prognosis of patients with acute cerebral hemorrhage; therefore, early clinical prevention has an important clinical value in patients su ering from cerebral hemorrhage VAP. Our results showed that age > 65 years, smoke, coronary heart disease, diabetes, chronic obstructive pulmonary disease (COPD), ICU and hospital stay, and days on mechanical ventilation were risk factors of VAP. e respiratory physiological function in the elderly decreased gradually with the increase of age, the muscle of the respiratory muscle gradually shrank, the elasticity of the lung tissue decreased gradually, and the cough and expectoration movement decreased signi cantly [24][25][26]. Meanwhile, the respiratory mucosal atrophy and mucinous gland functions of the patients with senile cerebral hemorrhage were decreased signi cantly, thus reducing the local defense function of the respiratory tract which easily leads to VAP infection.
Smoking can lead to damage to the respiratory system, resulting in shorter respiratory tract cilia, irregular, and ciliary movement disorders, to reduce the local defense capacity of the respiratory tract, which also easily leads to the occurrence of VAP. ICU time and longer duration of mechanical ventilation are risk factors of acquired pneumonia in ICU patients su ering from acute cerebral hemorrhage. is is because severe infection in ICU to the patients occurred more easily in the hospital, and the use of a respirator is a risk factor of VAP [15,27]. e number of days of hospitalization in the ICU and the increase in the number of days of ventilator use in patients with acute cerebral hemorrhage linearly increased the incidence of infection. It should be strictly controlled in ICU and during the use of mechanical ventilation to reduce the incidence of VAP.
In summary, this study suggests that patients with VAP can cause adverse prognosis including increased morbidity of acute cerebral hemorrhage and increased bleeding rate. Age > 65 years, smoke, coronary heart disease, diabetes, chronic obstructive pulmonary disease (COPD), ICU and hospital stay, and days on mechanical ventilation were independent risk factors of VAP. It should be strictly controlled in ICU and during the use of mechanical ventilation to reduce the incidence of VAP.

Conflicts of Interest
e authors declare that they have no con icts of interest.